1. Field of the Disclosure
Aspects of the disclosure relate to a plug-in fuel pump power bypass/test system.
2. Description of the Related Art
Various 2007 to 2014 model year Chrysler®, Jeep®, Dodge®, and Volkswagen® vehicles contain a particular style of fuse box called a Totally Integrated Power Module (TIPM). These fuse boxes have an inherent problem with the circuit board mounted fuel pump relay, insofar as the fuel pump relay often fails after approximately three to six years of operation.
In normal operation, the fuel pump relay serves as a conduit, transferring power to the electric fuel pump coupled to the fuel tank of the vehicle. When the vehicle is first turned on (via the ignition switch), power is applied to the electromagnetic coil in the fuel pump relay, causing the fuel pump relay to switch to the normally open position and allow current to pass through to the fuel pump, which activates and pumps the fuel (e.g., gasoline, diesel, etc.) necessary to start the engine. When the vehicle is turned off, power is removed from the electromagnetic coil in the fuel pump relay, causing the fuel pump relay to switch to the normally closed position via a spring return mechanism, thereby cutting off current to the fuel pump.
The fuel pump relay in a TIPM is a single relay that can intermittently fail to switch to the normally open position when power is applied to the electromagnetic coil, preventing the vehicle from starting, since no power is provided to the electric fuel pump. In this situation, the vehicle acts as if it is out of fuel without triggering any sensors or illuminating any dashboard warning lights. Fuel pump relays can also fail when the normally open contacts essentially “weld” themselves together due to high resistance and excessive heat, which can cause the fuel pump to remain powered on after the vehicle is turned off (thereby draining the battery). In a small percentage of vehicles, the electromagnetic coil in the fuel pump relay can fail, preventing the contacts from switching to the normally open position and resulting in no power delivered to the fuel pump. Additionally, some vehicles may experience low idle or stalling issues as the fuel pump relay turns on and off at varying rates while driving, creating safety issues.
There are existing solutions to address a defective fuel pump relay, but each has drawbacks. For example, in 2014, a recall was implemented for certain 2011 to 2013 model year vehicles, such as the Dodge® Durango™ and Jeep® Grand Cherokee™, to address failing fuel pump relays on the TIPM fuse box. This recall requires dealer installation of an external fuel pump relay where two wires are cut and one wire is spliced within several wire harnesses under the fuse box. Although many affected vehicle owners find this solution to be functional, many in the automotive industry advise against cutting wires under the fuse box. In addition, numerous other vehicles with the same faulty fuel pump relay were not part of the recall, and the cost associated with such an external relay installation for non-affected vehicle owners is high. For example, such an installation may cost the vehicle owner from $400 to $600.
Another solution is to repair the fuse box. Here, the fuse box is sent to a repair shop and broken down to the circuit board level. This is an effective solution insofar as the faulty fuel pump relay is replaced. However, the vehicle is inoperable while the repair is being performed, which can take days to weeks. Such a repair is also costly, for example, $300 or more. In addition, because the vehicle owner often removes and reinstalls the fuse box in order to be able to send it away to the repair shop, some vehicle owners may damage the fuse box during removal from the vehicle and/or fail to reinstall it properly after the repair.
Yet another solution is to replace the fuse box entirely. Replacing the fuse box with a new or used fuse box can be the most expensive solution because it requires removal, installation, and potentially reprogramming of the fuse box. It may take up to an hour or more to remove the old fuse box from a vehicle and reinstall the new or used fuse box. In some cases, used fuse boxes must be reprogrammed by a dealer, which can add another $100 to the cost. The vehicle owner also risks purchasing a used fuse box that has not been properly refurbished or contains relays that fail in a short period of time. Purchasing and replacing the fuse box can cost approximately $350 to $1,200.
Yet another solution is a bypass jumper cable available from Vertical Visions LLC that can bypass a faulty fuel pump relay by using power from another fuse slot in the fuse box. Specifically, when the cable is plugged into two fuse slots in the fuse box, it can check the fuel pump when the vehicle is turned off, test the +12 voltage direct current (VDC) output from the existing fuel pump relay, and, if the fuel pump relay is faulty, can bypass the fuel pump relay by using power from another fuse slot. However, this solution has several limitations, such as no remote start capability, unknown safety issues during a crash, etc., which precludes it from being a viable permanent solution.